QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

7 km NNE of Fontana, CA

· 6.5 km deep · released about 1,500 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 62 kmLos Angeles County 77 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Magnitude
M 3.1 (ml)
Depth
6.5 km below the surface
Felt
379 reports · strongest reported intensity III
Measured shaking
intensity III (ShakeMap)
Nearest
Orange County, 62 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 87 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 379 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1,500 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 220,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 9,800× the energy of this one
  3. Magna, Utah 2020 M 5.7 6,900× the energy of this one
  4. This earthquake M 3.1 about 1,500 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.6× more

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

Where

Epicentre 34.1572, -117.4278. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Orange County, CA 62 km (39 mi) NNE of here earthquakes near Orange County
Los Angeles County, CA 77 km (48 mi) E of here earthquakes near Los Angeles County
San Bernardino County, CA 138 km (86 mi) SW of here earthquakes near San Bernardino County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

57 earthquakes have been recorded within 50 km since this one.

  1. 1.9 7 km SSE of Home Gardens, CA
  2. 2.3 6 km NNE of Running Springs, CA
  3. 1.5 6 km N of Running Springs, CA
  4. 1.9 6 km NNE of Running Springs, CA
  5. 2.3 4 km SE of Ontario, CA
  6. 1.9 6 km NNE of Running Springs, CA
  7. 1.6 4 km SE of Yucaipa, CA
  8. 1.7 7 km N of Fontana, CA
  9. 1.6 6 km ENE of Yucaipa, CA
  10. 2.4 4 km SE of Devore, CA
  11. 1.5 7 km N of Beaumont, CA
  12. 1.6 5 km ENE of Muscoy, CA
  13. 1.9 8 km NNE of Beaumont, CA
  14. 2.0 10 km NNE of Trabuco Canyon, CA
  15. 1.8 0 km NNE of Redlands, CA

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 4.4 on 2018-08-29 — it released about 72 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.